Memory Controller State Group Backup for Sudden Power-Off Recovery
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Solution Overview
Problem
During sudden power-off (SPO) events in nonvolatile memory devices, existing technologies face challenges in efficiently backing up and recovering multi-bit data, leading to increased auxiliary power and memory capacity requirements.
Innovation Solution
The proposed method involves preprogramming multi-page data to memory cells with threshold voltages corresponding to specific states, generating a state group code with fewer bits, backing up this code, and recovering the data after power restoration to reprogram the cells accurately, reducing the need for extensive auxiliary power and memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data backup is performed for memory cells programmed in MLC mode when SPO occurs, then data reliability is improved, but the required capacity of auxiliary power supply increases
Solution Approach 1:
The patent segments the data backup process into two parts: first, pre-programming multi-page data to memory cells; second, generating and backing up a compressed state group code that represents the programmed states. This segmentation allows selective backup of only the essential state information rather than all raw data, reducing power requirements while maintaining reliability.
Solution Approach 2:
The patent creates a compressed representation (state group code) of the original multi-page data and backs up this copy instead of the full data set. The state group code contains sufficient information to recover and verify the original data states, enabling reliable data recovery with significantly reduced power and storage requirements.
2Quantity of substance
If multi-page data is preprogrammed with threshold voltages corresponding to multiple states, then data storage capacity is improved, but the complexity of data recovery and reprogramming increases
Solution Approach 1:
The patent performs preliminary organization of data into state groups and generates compressed state group codes during the preprogramming phase. This preliminary action simplifies subsequent recovery operations, as the compressed codes provide a straightforward reference for verifying and reprogramming memory cells without requiring complex analysis of the original multi-page data.
Solution Approach 2:
The patent transforms the original multi-page data into a different parameter representation (state group code) that captures the essential information in a more compact form. This parameter transformation reduces the complexity of data recovery operations while preserving all necessary information for accurate reprogramming.
3Use of energy by moving object
If state group code with fewer bits is generated and backed up instead of full multi-page data, then auxiliary power requirements are reduced, but measurement precision of data state verification decreases
Solution Approach 1:
The patent implements partial backup by storing only the essential state group code information rather than complete multi-page data. The state group code contains just enough information to verify and recover data states, providing sufficient precision for reliable operation while significantly reducing power and storage requirements.
Data Source
AI summary
An operating method of a memory system includes preprogramming multi-page data of a memory controller to a nonvolatile memory device, generating a state group code based on multi-bit data of the multi-page data, and each state group data of the state group code having less number of bits than corresponding multi-bit data, detecting sudden power-off occurring after the preprogramming, backing up, in response to the detecting of the sudden power-off occurring, the state group code to the nonvolatile memory device, recovering, after power is recovered from the sudden power-off, the multi-page data from the nonvolatile memory device, based on the state group code, reprogramming the multi-page data to the nonvolatile memory device, and reprogramming, in response to the detecting of the sudden power-off not occurring, the multi-page data of the memory controller to the nonvolatile memory device.